Fluorine and Water Reaction | F2 + H2O

Fluorine (F2), the most electronegative element reacts with water in a different way compared to other halogens do. According to the amount of fed and rate of feeding to water, products given by the reaction may vary. In this tutorial, we will learn those reactions, products and how to balance fluorine and water reaction.

Fluorine and water reaction is different from how other halogens react with water because fluorine's electronegativity is much greater than other halogens. (Fluorine's is the most electronegative element in periodic table)

fluorine and water reaction

Water and fluorine reaction will give products as below.

  1. Less amount of fluorine gas is fed slowly to water, this will give hydrogen fluoride and oxygen gas as products.
  2. Excess amount of fluorine gas is fed fast to water, this will give hydrogen fluoride and ozone as products.

Less amount of fluorine gas is fed slowly to water, this will give hydrogen fluoride and oxygen gas

Oxygen atoms in the water molecules are oxidized to oxygen gas and fluorine is reduced to hydrogen fluoride (HF). Therefore, this reaction is a redox reaction.

2F2 + 2H2O → 4HF + O2

Hydrogen fluoride is a weak acid. This is a good example for water is oxidized to oxygen gas reaction.

Excess amount of fluorine gas is fed fast to water, this will give hydrogen fluoride and ozone

Hydrogen fluoride is given in this reaction too. But oxygen in the water is oxidized to ozone (O3).

3F2 + 3H2O → 6HF + O3

Ozone is a toxic gas in ground level.

Produce F2O by the reaction of water and fluorine

When fluorine gas is distilled through cold water (at low temperature), oxygen difluoride (F2O) is given as the product. But due to less solubility, this method is not efficient.

Therefore, fluorine is dissolved in 2% dilute NaOH solution to get F2O in a efficient way.

F2 + H2O → F2O + H2

Hydrogen gas is produced in this reaction as a product. Also this is a rare occasion when oxygen show positive oxidation number.

How to balance reactions

All reactions of water and fluorine are redox reactions. We will look how to balance them in redox method.

Balance F2 + H2O → HF + O2

First, find oxidation numbers of each element in the left side and right side of the equation. Then, determine which atoms' oxidation numbers are changed when going to the right side.

  • Oxidation number of fluorine has been changed from 0 to -1.
  • Oxidation number of oxygen has been changed from -2 to 0.

Identify oxidation and reduction. Fluorine gas is reduced to hydrogen fluoride while water is oxidized to oxygen gas.

Then equal the number of atoms of the chemical equation which are undergone through oxidation and reduction.

Take the oxidation number differences of oxidation and reduction processes.

how to balance water and fluorine reaction

Fluorine (F2)

Fluorine is a highly toxic pale yellow diatomic gas at standard conditions. It is the most electronegative element in the periodic table and reacts with so many elements to form different compounds.

Hydrogen fluoride (HF)

In both reactions, hydrogen fluoride is given when fluorine reacts with water. Also, hydrogen fluoride is a highly dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. But, in these reaction you will get aqueous hydrogen fluoride solution.

Aqueous HF is a weak acid.

Questions asked by students. Ask your question and find the answer free.

Fluorine gas and water vapor to form hydrogen fluoride gas and oxygen

Yes. When fluorine gas meets water vapor, hydrogen fluoride (HF) and oxygen gas (O2) are produed.

Why I should be careful when fluorine gas is sent to water? I asked this question because, this reaction was not done in our school and when we asked it from the teacher, she said that, we don't have fluorine gas in our lab.

In this reaction, ozone gas can be produced as a product. Ozone is a highly toxic gas in ground level. Also, fluorine is a toxic gas and a very strong oxidizing agent.

How ozone gas is produced when fluorine reacts with water?

If amount of fluorine is high or feeding rate is high, ozone can be given.

Can fluorine and water reaction give ozone and oxygen as products.

Ozone or oxygen is given according to the available fluorine amount. When fluorine is in excess amount, ozone will be given. But when amount of fluorine is reduced, oxygen can be given as the product. Therefore, during the reaction, ozone and oxygen can be given as products.

F2 react with water, but why iodine does not react?

Due to fluorine's higher electronegativity, fluorine can oxidize oxygen atom in water. Iodine is not soluble in water.

How fluorine is different from other halogens when they react with water?


Solubility of halogens in water is reduced when going down the group. It means solubility of Chlorine is lower than Fluorine.

When chlorine gas dissolves in water, it gives hydrochloric acid and hypochlorous acid mixture.

Cl2 + H2O → HCl + HOCl

When bromine dissolve in water it gives products as chlorine gives with water. But, solubility of bromine in water is poor. So giving hydrobromic acid (HBr) and hypobromous acid (HOBr) is not success such as formation of HCl and HOCl by chlorine.

does fluorine react with water?

Yes. Fluorine reacts with water violently.

does F2 gas dissolve in water?

Yes. Fluorine dissolve very well in water and reacts readily with water.

What is more soluble F2 or Cl2 or Br2 or I2?

F2 is the most soluble halogen and F2 reacts with water very fast than other halogens.

Is reaction of f2 with water similar to cl2 with water?

Both halogeh reac differently with water. Due to higher electronegativity, fluorine reacts violently with water and produce oxygen gas. But, chlorine dissolve in water and form HCl and HOCl.

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